NULLSET
Set to 2 different clues across 2 published puzzles, most often “It has zero measure, in math” — The New York Times, Friday, 28 May 2010.
7 letters
Every clue on record, most used first
- It has zero measure, in mathonce
The New York Times — Friday, 28 May 2010
- It's emptyonce
The New York Times — Friday, 5 April 2002